Seat belt system

ABSTRACT

A vehicle seat belt system for use in automobiles, buses, airplanes, boats and the like. A seat system responsive to the occupancy of a seat by a passenger and use of the seat belt for that seat. A switch system actuated by said seat system. A signal system controlled by the switch system for signaling non-use of a seat belt of an occupied seat. A vehicle power system controlled by the switch system. The vehicle power system being inoperative when the seat belt of an occupied seat is not in use. A delay cut-off switch in said switch system which delays for a predetermined time interval the rendering of the vehicle power system inoperative when a seat belt is disengaged during operation of the vehicle.

Unlted States Patent [1 1 1 3,784,972

Hults Jan. 8, 1974 SEAT BELT SYSTEM 57 ABSTRACT [76] Inventor: Arthur B1.10m ReChlmg A vehicle seat belt system for use in automobiles,

Cahf' 90606 buses, airplanes, boats and the like. A seat system re- [22]Filed: Jan. 24, 1972 sponsive to the occupancy of a seat by a passengerand use of the seat belt for that seat. A switch system [21] Appl-220,254 actuated by said seat system. A signal system controlled by theswitch system for signaling non-use of a 52 US. Cl 340/52 E, 307/ SB,180/82 (2 Seat belt of an Occupied Seat A vehicle power system 51 Int.l. B60r 21/10 Controlled by the switch system The vehicle power [58]Field of Search 340/52 E, 278; System being inoperative when the seatbelt of an 307/10 180/82 C cupied seat is not in use. A delay cut-offswitch in said switch system which delays for a predetermined time [56]References Cited interval the rendering of the vehicle power system in-UNITED STATES PATENTS operative when a seat belt is disengaged duringoperation of the vehicle. 3,074,055 1/1963 Rudolph et al 340/52 E X338L268 4/1968 Boblitz 340/278 X 3,449,714 6/l969 Farley, Jr 340/278 XPrimary Examiner- Alvin H. Waring Att0rneyFord W. Harris, Jr. et al.

6 Claims, 4 Drawing Figures /2 /Z: FRONT PA SSEA/ERS Q 42a 0 Z/ BELTEll/E /4 m /6 9 BELT 24a 27 II I @fi y /4/ 57 42/ 47 37 W56 44 43 33clifi'a' 555 s56 45 DELAY 53,1 D

E O 3/ 4629 25a 49 BELT 4 REA/3 PA5$M6EQ5 -50 50a 0 36a SEAT BELT SYSTEMBACKGROUND OF THE INVENTION The present invention is directed to avehicle seat belt system that signals when the seat belt of an occupiedseat is disengaged. More particularly, the invention is directed to aseat belt system that controls the vehicles power system and preventsmovement of the vehicle from a standstill and deactivates the powersystem after a predetermined delay when the vehicle is in motion uponthe disengagement of a seat belt for an occupied seat.

Although the safety virtues of vehicle seat belts are well known andwell advertised, and most, if not all,

past l965 automobiles are equipped with seat belts, there is evidencethat less than half the drivers and passengers of vehicles use them.Safety committees have advocated legislation making the non-use ofavailable seat belts a ground of contributory negligence in vehicleaccident suits and auto companies have installed flashing signalsreading SEAT BELTS or the like on automobile dashboards to no avail. Theautomobile safety experts have come to realize that availability,eduction, warning signals and threatened punitive legislation are notenough to comple the majority of people to use seat belts.

SUMMARY OF THE INVENTION A seat belt system having an electrical source,a seat system, a switch system and a signal system. The switch systembeing electrically actuated by actuating means. The seat system having adrivers seat belt switch which is responsive to use and nonuse of theseat belt. The drivers seat belt switch connecting the actuating meansto the electrical source when the seat belt is in use. The switch systemconnecting the signal system to the electrical system when the actuatingmeans is not electrically energized.

Said seat system optionally containing one or more passenger seatcircuits. The passenger seat circuit'having a seat switch which isresponsive to occupancy of the seat and a passenger seat belt switchwhich is responsive to use of the passenger seat belt. The seat switchelectrically connects the driver seat belt switch to the actuating meanswhen the passenger seat is unoccupied and it electrically connects thedriver seat belt switch to the passenger seat belt switch when the seatis occupied. The passenger seat belt switch being electrically connectedwith the actuating means when the passenger seat belt is in use. Inaddition said seat belt system optionally includes a vehicle powersystem which requires electrical energy to operate. The switch systemelectrically connects the power system to the electrical source when theactuating means is electrically energized. In another embodiment, theseat belt system includes a delay cut-off switch having electricallypowered control means. The switch system electrically connecting thecontrol means to the electrical source when the actuating means iselectrically energized. The cut-off switch electrically connecting thepower system to the electrical source when the control means iselectrically energized. The cut-off switch breaking the electricalconnection between the power system and the electrical source after apredetermined time interval following the de-energization of the controlmeans.

DESCRIPTION OF THE DRAWINGS FIG. 1 is an electrical diagram of a seatbelt system incorporating the preferred embodiment of the presentinvention;

FIG. 2 is a sectional view of a seat belt strap anchor used in a seatbelt system;

FIG. 3 is a cross-sectional view taken along line 3-3 of FIG. 2; and

FIG. 4 is an electrical diagram of a seat belt incorporating anotherembodiment of the present invention.

DESCRIPTION OF THE INVENTION Referring to FIG. 1, the invention, a seatbelt system 10 includes an electrical power source 11, a seat system 12,a switch system 13, a vehicle power system 14 and a signal system 15.

The power source 11 includes a battery 16. One side of the battery 16 isconnected to a common ground 17 which is normally the metal frame orbody of the vehicle (not shown). The other side of the battery isconnected to one side of an ignition switch 18. The other side of switch18 is connected to the seat belt system 12 via lead 19.

The seat belt system 12 includes seat belt switches 21, 22 and 23 andseat switches 24 and 25. The lead 19 is electrically connected to oneend of the driver's seat belt switch 21 which, as are switches 22 and23, is equivalent to a single pole switch. The switch 21 is connected tothe drivers seat belt (not shown) and is open when the belt is not inuse and is closed when the belt is in use. The other side of switch 21is connected to an input pole 24a of the front passenger seat switch 24,which is, as is switch 25, equivalent to a single pole double throwswitch. The switch 24 is connected to the front passenger seat (notshown) and is responsive to the occupancy state of the seat. When theseat is unoc' cupied, the switch is as illustrated in FIG. 1. A pole 24bof switch 24 is electrically connected to a terminal 27. Another pole24c of switch 24 is electrically connected to one side of a passengerseat belt switch 22. The switch 22 is connected to the front passengerseat belt (not shown) and is responsive to the use of the belt. Theother side of switch 22 is electrically connected to terminal 17 whichis electrically connected to a rear passenger seat switch 25 via a lead28 and an input terminal 25a. A pole 25b of the switch 25 iselectrically connected to a terminal 29 and another pole 250 isconnected to one side of the rear passenger seat switch 23. The otherside of switch 23 is electrically connected to the terminal 29 which isconnected to the switch system 13 by lead 30. Switches 25 and 23 aresimilar in opera tion to switches 24 and 22 respectively.

The switch system 13 includes a magnetic relay switch 33 and a delayaction switch 34. Lead 30 is electrically connected to one side of asolenoid coil 35 ofv switch 33; the other side of coil 35 iselectrically connected to a lead 36 at a terminal 36a. The coil 35drives one end of a switch bar 37 from contact with a pole 33b to a pole330; a spring means (not shown) biases bar 37 to make contact with pole33b. The other end of bar 37 is electrically connected to pole 33a whichis electrically connected to a lead 38 at a terminal 39. One end of lead38 is electrically connected to a pole 40a of an emergency short-outswitch 40. The switch 40 has a switch bar 40b which is connected to thelead 19 via a lead 41 at a terminal 19a. The switch 40 has a second pole40c which is electrically connected to a lead 42. One end of lead 42 isconnected to a lead 50 and the other end is connected to one side of alamp 42a. The other side of the lamp 42a is connected to a common ground17a. The other end of lead 38 is electrically connected to an inputterminal 43 of the switch 34 which also has a control input terminal 44,a control ground terminal 45 and an output terminal 46.

The delay relay switch 34, which is normally open between terminals 43and 46, is an electrically actuated switch which closes the circuitbetween terminals 43 and 46 when current flows through the switchcontrol apparatus (not shown) via terminals 44 and 45. When the currentflow to the control apparatus is interrupted, the switch control opensthe circuit between terminals 43 and 46 after a predetermined timeinterval. Any conventional delay relay switch can be employed, such asthe Amperite Thermostatic Delay Relay, sold by the Amperite Co., lnc.,600 Palisade Ave., Union City, N. J. 07087, and described in theAmperite Bulletin No. TR-S l.

Pole 330 is electrically connected to terminal 44 via lead 47. Theterminal 45 is electrically connected to a ground lead 48 via lead 36 ata terminal 49. One end of lead 48 is connected to a common ground 17b.The vehicle power system 14 is electrically connected to the switch 34by the lead 50 at terminal 46. The lead 30 is electrically shorted tolead 50 at terminal 50a via a lead 31. The vehicle power systemillustrated includes an ignition coil 51 which is electrically connectedto lead 50 and a common ground 17c. The pole 33b is electricallyconnected to the signal system at a terminal 52.

The signal system 15 includes an electrically powered buzzer 55 and anelectric light 56. One side of the buzzer 55 is electrically connectedto terminal 52 via lead 57 and the other side is electrically connectedto lead 48 which in turn is electrically connected to lead 48 which inturn is electrically connected to ground 17a. The light 56 iselectrically connected on one side to lead 48 at terminal 58 and on theother side to the terminal 52.

The seat belt system illustrated in FIG. 4 is similar in many respectsto the system illustrated in FIG. 1, and elements common to both systemsare identified with the same numerals. Referring to FIG. 4, theinvention, a seat belt system 10 includes an electrical power source 11,a seat system 12, a switch system 13A, a vehicle power system(electrical ignition system) 14 and a signal system 15.

The seat system 12, described above, includes seat belt switches 21, 22and 23 and seat switches 24 and 25 and is connected to the switch system13A via lead 30.

The power source 11 is connected to the seat system 12 as describedabove.

The switch system 13A includes a magnetic relay switch 33A and a delayaction switch 34A. Lead is electrically connected to one side of asolenoid coil 35 of switch 33A; the other side of coil 35 iselectrically connected to a lead 36 at a terminal 36a. The coil 35drives one end of switch bar 37 away from electrical contact with a pole33d to a pole 332; a spring means (not shown) biases bar 37 to makecontact with pole 33d. The other end of bar 37 is electrically connectedto pole 33a which is electrically connected to a lead 38 at a terminal39. One end of lead 38 is electrically connected to lead 19 at terminal19b via switch 40 and lead 41; the other end of lead 38 is electricallyconnected to input terminal 43a of the switch 34A which also has acontrol input terminal 44a, a control ground terminal 45a and an outputterminal 46a. The switch 40 can be electrically connected to the powersystem 14 and the lamp 42a as described above.

The delay relay switch 34A, which is normally closed between terminals43a and 46a, is an electrically actuated switch which opens the circuitbetween terminals 43a and 46a when current flows through the switchcontrol apparatus (not shown) via terminals 44a and 45a. When thecurrent flow to the control apparatus is commenced, the switch controlopens the circuit between terminals 43a and 46a after a predeterminedtime interval. Any conventional delay relay switch can be employed, suchas the Amperite Thermostatic Delay Relay, sold by the Amperite Co.,lnc., 600 Palisade Ave., Union City, NJ. 07087, and described in theAmperite Bulletin No. TR-8I.

Pole 33d is electrically connected to terminal 440 via lead 47a. Theterminal 45a is electrically connected to a ground lead 48 via the lead36 at a terminal 49. The vehicle power system 14 is electricallyconnected to the terminal 46a by lead 50. The vehicle power system 14includes an ignition coil 51, as described above. The pole 33d is alsoelectrically connected to the signal system 15 at the terminal 52.

The signal system 15 includes an electrically powered buzzer 55 and anelectric light 56 and is connected to the terminals 49 and 52, asdescribed above.

In FIG. 2, a seat belt anchor device 60 is illustrated. The anchor 60has a frame 61 and an anchor plate 62 which are secured to one anotherfor hinged movement by hinge assembly 63 (see FIG. 3). The plate 62 hasan aperture 64 adapted to receive a bolt or rivet (not shown) forsecuring the anchor 60 to a vehicle. The frame 61 has an elongatedaperture 65 which is adapted to receive a bushing 66 for slidingmovement. First and second sleeves 67 and 68, respectively, arejournaled on the bushing 66 above and below the frame 61. An attachmentlug 69 is journaled on the bushing 66; the lug has a slit aperture 70(see FIG. 3) through which the end of a seat belt strap 71 is passed,folded back and secured to the strap. A threaded bolt 74 and a threadednut 75 secure the assembly of bushing 66, sleeves 67 and 68, and lug 69between first and second washers 76 and 77, respectively (hereinafterreferred to as the assembly 78). A switch 79 is mounted on the frame 61so that sleeve 68 can engage and depress the switch lever 79a when theassembly 78 is slid toward the switch. First and second plates 82 and83, respectively, are positioned above and below the frame 61 andsecured thereto by hollow pillars 84 and 85 and threaded machine bolts86 which pass through plate 82, pillar 84, frame 61 and pillar 85 andengage complementary threaded apertures in plate 83. A spring 87, havingits middle portion spirally wound about one of the pillars 85, one endseated about the outer periphery of sleeve 67, and the other endengaging another pillar 85, biases the assembly toward the switch 79.

Operation of the Seat Belt System The operation of the system 10 willfirst be described with a driver alone occupying the vehicle. If thedriver fails to fasten his seat belt, the vehicles power system will nowoperate when the ignition switch 18 is closed or turned on. When thedrivers seat belt is not fassystem via lead 41, switch 40, bar 4012,pole 40a,

lead 38, terminal 39, pole 33a, bar 37 pole 33b and terminal 52. Thelight 56 and buzzer 55 of the signal system, in the case of anautomobile, will normally be in i or under the dashboard to give thedriver notice that his seat belt is not fastened. In its unenergizedstate, switch 33 does not direct current to the controls of switch 34via terminal 44. When the controls of switch 34 are not electrified, thecircuit between terminals 43 and 46 is open and no current passes to thevehicle power system 14 via the switch 34. In addition, the open switch21 prevents current flow through the lead 30 and the lead 31 to the lead50, thus rendering the system 14 inoperative.

When the driver fastens his seat belt, switch 21 closes and the vehiclepower system is energized via lead 30, lead 31 and lead 50, and thesolenoid coil 35 is electrified via switches 21 and 24, pole 24b,terminal 27, lead 28, switch 25, pole 25b, terminal 29 and lead 30. Theelectrified coil 35 throws or switches the bar 37 from contact with thepole 33b to contact with the pole 330. The switching of poles cutscurrent flow to the signal system 15, and directs current to thecontrols of switch 34, starting from bar 37, through pole 33c lead 47,ter minal 44, the control apparatus of switch 34, terminal 45, lead 36,terminal 49 and to the ground 17!). The energization of the controls ofthe switch 34 closes the circuit between terminals 43 and 46 andelectrically connects the power system 14 with the electrical powersource starting with terminal 46, through lead 50 to coil 51 permittingoperation of the vehicle power system 14. When energized, conventionaldelay relay switches require a short period to close the circuit betweenterminals 43 and 46. Thus lead 31 provides that the power system 14 canbe operated immediately without delay when switch 21 is closed.

If the driver unfastens his seat belt during the operation of thevehicle, the seat belt switch 21 opens and causes a power loss to lead50 via lead 31 and to the switch system 13, whereupon solenoid switch 33de energizes and the biasing means of switch 33 causes bar 37 to switchfrom pole 330 to pole 33b. This switching energizes the signal system 15as described above and furnishes a warning to the driver that his beltis unfastened. Simultaneously, the de-energization of switch 33 cuts thecurrent flow to the control mechanism of switch 34. The switch controlbreaks of switches off the circuit between terminals 43 and 46 causing apower loss to the vehicle power system 14. In addition, there is nocurrent flow from lead via lead 31 and lead 50 to the system 14rendering the system inoperative. For purposes 'of safety. the controlmechanism of switch 34 delays breaking the circuit between terminals 43and 46 for a predetermined period of time to keep vehicle power systemenergized in order to give the driver sufficient time to fasten his seatbelt or bring the vehicle, in

causes the energization of switch 34, and the deenergization of thesignal system 15.

When a passenger occupies a seat in the vehicle the operation of thevarious systems, except for the seat system 12, are not altered andfunction as described above. With respect to the seat system 12, when apassenger seat is occupied by a passenger, a switch, such as switch 24,is actuated causing the switch to break the circuit to pole 24b andclose the circuit to pole 24c. If the passenger fails to fasten his seatbelt, his seat belt switch 22 remains open and prevents current flowfrom seat switch 24, via pole 24c, to terminal 27 and on to the switchsystem 13 and vehicle power system 14 as described above. This in turcauses energization of the signal system 15 when the ignition switch 18is closed. When the passenger seat belt is fastened, switch 22 closesallowing current flow to the vehicle power system l4 and the switchsystem 13, which in turn deenergizes the signal system 15 and permitsthe driver to operate the vehicle power system 14 as described above. Ifthe vehicle is in operation when a passenger unfastens his seat belt,switch 22 opens and breaks the circuit or electrical connection betweenthe electrical source 16 and the switch system 13 and the power system14. This in turn causes the signal system 15 to be electrified andde-energizes the control of switch 34 as described above. If thepassenger timely fastens his seat belt before switch 34 cuts off powerto the vehicle power system 14, the operation of the vehicle will not beinterrupted.

The rear passenger seat system works in the same manner as the frontpassenger seat. That is, when the rear seat is occupied, the switch 25closes contact between the pole 25c and the lead 28 and breaks contactbetween the pole 25b and the lead 28. If the passenger fails to securehis seat belt, the switch 23 remains open and no current flows to thelead 30. When the passenger secures his belt, the switch 23 closesconnecting the lead 30 to the battery 16 as described above.

Additional seat systems similar to the front and rear passenger seatsystems described above can be added to circuits l0 and 10A (describedbelow) in series.

The emergency switch 40 provides a means of opcrating the vehicle when abreakdown occurs in the system 10. When the bar 40b is switched to makecontact with the pole 400, the power system is connected to the ignitionswitch through lead 19, terminal 19a, lead 41, switch 40, and lead 42 tolead 50. The light 42c is also electrically connected to the ignitionswitch to give notice that emergency switch has been actuated.

The operation of the system 10A will first be described with a driveralone occupying the vehicle. If the driver fails to fasten his seatbelt, the vehicles power system will operate for a predetermined timeonly when the ignition switch 18 is closed. When the drivers seat beltis not fastened, seat belt switch 21 remains open and prevents currentfrom flowing through switch 21 to the coil 35 of switch 33A and to thevehicle power system 14 via lead 38, switch 34A and lead 50. In itsunenergized state, that is, when the coil 35 is not electrified, switch33A directs current from terminal 19a through the signal system 15 vialead 41, switch 40, lead 38, terminal 39, pole 33a, bar 37, pole 33d andterminal 52. In its unenergized state, switch 33A also directs currentto the controls of switch 34A via terminal 44a. When the controls ofswitch 34A are electrified, the circuit between terminals 43a and 46a isopen and no current passes to the vehicle power system 14 via lead 50.

When the driver fastens his seat belt, switch 21 closes and the vehiclepower system is energized via lead 38 terminals 43a and 46a and lead 50,and the solenoid coil 35 is electrified as described above. Theelectrified coil 35 throws the bar 37 so as to disengage it from contactwith the pole 33d and cut the current flow to the signal system and thecurrent flow to the controls of switch 34A. The de-energization of thecontrols of the switch 34A closes the circuit between the terminals 43aand 46a and electrically connects the power system 14 with theelectrical power source 11.

If the driver unfastens his seat belt during the operation of thevehicle, the seat belt switch 21 opens and causes a power loss to theswitch system 13A, whereupon solenoid switch 33A de-energizes and thebiasing means of switch 33 causes bar 37 to come in electrical contactwith the pole 33d. This switching energizes the signal system 15 asdescribed above and furnishes a warning to the driver that his belt isunfastened. Simultaneously, the de-energization of switch 33Aelectrically connects the power source 11 to the control mechanism ofswitch 34A which causes a break in the circuit between the terminals 43aand 46a and a resulting power loss to the vehicle power system 14. Forpurposes of safety, the control mechanism of switch 34A delays breakingthe circuit between terminals 43a and 46a for a predetermined period oftime to keep the vehicle power system 14 energized in order to give thedriver sufficient time to fasten his seat belt or bring the vehicle, inthe case of an automobile, to a stop in a safe place. When the driverfastens his belt, switch 21 closes, causing the energization of switchsystem 13a and the system 14 and the de-energization of the signalsystem 15 as described above.

The operation of circuit 10A with respect to the passenger seat switchsystem and the emergency switch 40 is identical to that described abovefor circuit 10.

The seat belt anchor device 60 has a switch mechanism responsive tofastening and unfastening of the belt and is ideally suited for use inthe seat belt system 10. When the belt 71 is unfastened, the assembly 78is biased toward the switch 79 by spring 87. The sleeve 66 engages anddepresses switch lever 79a causing switch 79 to open. When the belt 71is fastened, the belt pulls assembly '78 away from switch 79 and lever79a causing the switch to close. The elongated aperture 65 is ofsufficient length to eliminate inadvertent engagement of the switchlever 79a with assembly 78 when the seat belt 71 is fastened.

The invention is not limited to the embodiment described above. Forexample, the seat belt system may be comprised of a plurality ofpassenger seat systems each connected in series between the driver seatbelt switch 21 and terminal 29. Seat belt anchor systems and switchesother-than anchor 60 may be employed in the invention. in addition,switch 33 can be a solenoid switch or the like and delay relay switch 34can be any electrically powered switch that delays cut off afterdeenergization. Furthermore, lead 50 can energize components of thevehicle power system 14, other than the ignition coil 51, such as anelectric fuel pump, transmission lock or brake, master battery switch orthe like.

I claim:

1. In a seat belt system for a vehicle having a driver's seat with afastenable drivers seat belt and having an electrical ignition systemincluding an ignition switch, the combination of:

a. first energizing means responsive to fastening of the drivers seatbelt and to closure of the ignition switch for energizing the ignitionsystem;

b. first de-energizing means independent of the ignition switch andresponsive to subsequent unfastening of the drivers seat belt, afterenergization of the ignition system, for de-energizing the ignitionsystem; and

c. time delay means for activating said first deenergizing means onlyafter a predetermined time delay following unfastening of the driver'sseat belt.

2. A seat belt system as defined in claim 1 wherein said firstenergizing and dc-energizing means include a drivers seat belt switch inseries with the ignition switch and closable upon fastening of thedrivers seat belt.

3. A seat belt system according to claim 1 for a vehicle also having apassengers seat with a fastenable passengers seat belt, including:

a. second energizing means responsive to the presence of a passenger inthe passengers seat and to fastening of the passengers seat belt foractivating said first energizing means if the driver's seat belt isfastened and the ignition switch is closed;

b. second de-energizing means independent of the ignition switch andresponsive to subsequent unfastening of the passengers seat belt with apassenger in the passengers seat, after energization of the ignitionsystem, for activating said first deenergizing means to de-energize theignition system; and

c. said time delay means activating said first deenergizing means onlyafter a predetermined time delay following unfastening of the passengersseat belt.

4. A seat belt system as set forth in claim 3 wherein said secondenergizing and de-energizing means include a passenger seat switchresponsive to the pres ence of a passenger in the passengers seat and apassengers seat belt switch closable upon fastening of the passengersseat belt, said passenger seat switch including means for placing saidpassengers seat belt switch in series with the ignition switch when apassenger is in the passengers seat.

5. A seat belt system according to claim 1 including signal means forsignalling that the drivers seat belt is unfastened.

6. A seat belt system as defined in claim 3 including signal means forindicating that the passengers seat belt is unfastened if a passenger isin the passenger's

1. In a seat belt system for a vehicle having a driver''s seat with afastenable driver''s seat belt and having an electrical ignition systemincluding an ignition switch, the combination of: a. first energizingmeans responsive to fastening of the driver''s seat belt and to closureof the ignition switch for energizing the ignition system; b. firstde-energizing means independent of the ignition switch and responsive tosubsequent unfastening of the driver''s seat belt, after energization ofthe ignition system, for deenergizing the ignition system; and c. timedelay means for activating said first de-energizing means only after apredetermined time delay following unfastening of the driver''s seatbelt.
 2. A seat belt system as defined in claim 1 wherein said firstenergizing and de-energizing means include a driver''s seat belt switchin series with the ignition switch and closable upon fastening of thedriver''s seat belt.
 3. A seat belt system according to claim 1 for avehicle also having a passenger''s seat with a fastenable passenger''sseat belt, including: a. second energizing means responsive to thepresence of a passenger in the passenger''s seat and to fastening of thepassenger''s seat belt for activating said first energizing means if thedriver''s seat belt is fastened and the ignition switch is closed; b.second de-energizing means independent of the ignition switch andresponsive to subsequent unfastening of the passenger''s seat belt witha passenger in the passenger''s seat, after energization of the ignitionsystem, for activating said first de-energizing means to de-energize theignition system; and c. said time delay means activating said firstde-energizing means only after a predetermined time delay followingunfastening of the passenger''s seat belt.
 4. A seat belt system as setforth in claim 3 wherein said second energizing and de-energizing meansinclude a passenger seat switch responsive to the presence of apassenger in the passenger''s seat and a pasSenger''s seat belt switchclosable upon fastening of the passenger''s seat belt, said passengerseat switch including means for placing said passenger''s seat beltswitch in series with the ignition switch when a passenger is in thepassenger''s seat.
 5. A seat belt system according to claim 1 includingsignal means for signalling that the driver''s seat belt is unfastened.6. A seat belt system as defined in claim 3 including signal means forindicating that the passenger''s seat belt is unfastened if a passengeris in the passenger''s seat.